arch/sparc/lib/atomic32.c

   1 /*
   2  * atomic32.c: 32-bit atomic_t implementation
   3  *
   4  * Copyright (C) 2004 Keith M Wesolowski
   5  *
   6  * Based on asm-parisc/atomic.h Copyright (C) 2000 Philipp Rumpf
   7  */
   8
   9 #include <asm/atomic.h>
  10 #include <linux/spinlock.h>
  11 #include <linux/module.h>
  12
  13 #ifdef CONFIG_SMP
  14 #define ATOMIC_HASH_SIZE        4
  15 #define ATOMIC_HASH(a)  (&__atomic_hash[(((unsigned long)a)>>8) & (ATOMIC_HASH_SIZE-1)])
  16
  17 spinlock_t __atomic_hash[ATOMIC_HASH_SIZE] = {
  18         [0 ... (ATOMIC_HASH_SIZE-1)] = SPIN_LOCK_UNLOCKED
  19 };
  20
  21 #else /* SMP */
  22
  23 #define ATOMIC_HASH_SIZE        1
  24 #define ATOMIC_HASH(a)          0
  25
  26 #endif /* SMP */
  27
  28 int __atomic_add_return(int i, atomic_t *v)
  29 {
  30         int ret;
  31         unsigned long flags;
  32         spin_lock_irqsave(ATOMIC_HASH(v), flags);
  33
  34         ret = (v->counter += i);
  35
  36         spin_unlock_irqrestore(ATOMIC_HASH(v), flags);
  37         return ret;
  38 }
  39
  40 void atomic_set(atomic_t *v, int i)
  41 {
  42         unsigned long flags;
  43         spin_lock_irqsave(ATOMIC_HASH(v), flags);
  44
  45         v->counter = i;
  46
  47         spin_unlock_irqrestore(ATOMIC_HASH(v), flags);
  48 }
  49
  50 EXPORT_SYMBOL(__atomic_add_return);
  51 EXPORT_SYMBOL(atomic_set);
  52